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2004 chevy trailblazer_ls
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Discussion Starter · #1 ·
so i was driving with the AC on and i had it on 5 then all of a sudden it turns off. so i switch it to off then cycle through the speeds everything works except for the #5 setting. any help? thank you
 

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2004 gmc
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Well, I'd at least wait until I was proven right to mark the issue SOLVED. ;)

Otherwise I might as well go around to all threads I merely guessed at the cure and mark THEM solved. :crackup: :woohoo:

It's actually an interesting statistic how many times it's the resistor/relay pack compared to the fuse. I went out and bought a spare J-case fuse just for this location, and have NEVER heard of one blowing.
 

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2004 chevy trailblazer_ls
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Discussion Starter · #5 ·
i went and checked the fuse and its fine. so im guessing its the resistor called the stealership and they said the same thing "did you check the fuse?" ; "could be a resistor for the blower unit" and then they tell me "we have to replace the blower unit for you" so im gonna order the part from parts4chevy and if that dont work oh well its only 40$
 

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Lousy criminal incompetent dealer that one is. What's their name? Get their greed and incompetence archived in Google, is my advice.

No need to wait to get it mail order. It's a popular failure item, and available cheaply in the aftermarket parts stores. Call around. $25-30. Did you read the thread to get the AC Delco part number?
 

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2004 chevy trailblazer_ls
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Discussion Starter · #7 ·
Lousy criminal incompetent dealer that one is. What's their name? Get their greed and incompetence archived in Google, is my advice.

No need to wait to get it mail order. It's a popular failure item, and available cheaply in the aftermarket parts stores. Call around. $25-30. Did you read the thread to get the AC Delco part number?
central chevy. i called again and they was $61 just for the resistor. im going to call around. advance wants $45 parts4chevy is the cheapest so far. it can wait i mean i have some air just not high. when it gets to like 90+ deg. im going to need high. but till them im not TOO worried about it. looks like a quick install. havent looked of delco # yet but im going to
 

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2002 chevy trailblazer_ls
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I find it odd that only 5 doesn't work. In my experience when the resistor goes the highest postion works as it is the full current setting. Are the TB's different in this regard?? Jeff
 

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2007 buick rainier
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I find it odd that only 5 doesn't work. In my experience when the resistor goes the highest postion works as it is the full current setting. Are the TB's different in this regard?? Jeff
I thought 5 went thru a relay,maybe on the resistor pack ????
 

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2004 chevy trailblazer_ls
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Discussion Starter · #11 ·
i have no clue how it works ill prolly pull it off and check it out before i buy a new one. ive seen a couple of cars where the highest setting only works but i donno :suicide:
 

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I find it odd that only 5 doesn't work. In my experience when the resistor goes the highest postion works as it is the full current setting. Are the TB's different in this regard?? Jeff
Yes, they're different. Read on.

I thought 5 went thru a relay,maybe on the resistor pack ????
A winner!

i have no clue how it works ill prolly pull it off and check it out before i buy a new one. ive seen a couple of cars where the highest setting only works but i donno :suicide:
How it really works is like this: Speeds 1-4 are obtained by a wire resistor that dissipates power meant to go to the blower. This slows down the blower, but seriously heats up the wire resistors. So the design of almost all vehicles puts these resistors in the airflow of the blower motor to cool 'em off.

Some older vehicles used a "no resistor" position of the switch to get full fan speed. But that meant the wiring to the switch had to handle the full blower motor current, and that's a waste of thick wire and makes the switch less reliable.

So on our design, there's a relay on the resistor pack, controlled by the normal switch, but capable of sending 40A from a different fuse to the blower. It's also a slight safety improvement, if you have a stalled blower motor from a mouse nest inside, and the 40A fuse blows if you try to run it on high speed, and then you take it apart and remove the mouse nest, it will continue to run on speeds 1-4 until you find a new 40A speed 5 fuse.

 

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Discussion Starter · #13 ·
Yes, they're different. Read on.

A winner!

How it really works is like this: Speeds 1-4 are obtained by a wire resistor that dissipates power meant to go to the blower. This slows down the blower, but seriously heats up the wire resistors. So the design of almost all vehicles puts these resistors in the airflow of the blower motor to cool 'em off.

Some older vehicles used a "no resistor" position of the switch to get full fan speed. But that meant the wiring to the switch had to handle the full blower motor current, and that's a waste of thick wire and makes the switch less reliable.

So on our design, there's a relay on the resistor pack, controlled by the normal switch, but capable of sending 40A from a different fuse to the blower. It's also a slight safety improvement, if you have a stalled blower motor from a mouse nest inside, and the 40A fuse blows if you try to run it on high speed, and then you take it apart and remove the mouse nest, it will continue to run on speeds 1-4 until you find a new 40A speed 5 fuse.


Roadie you are truly the TrailVoy GOD !! and a [email protected] good automotive scientist :thumbsup: ever thought of opening your own car shop ?
 

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2004 gmc
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...ever thought of opening your own car shop ?
:eek:fftopic: Not seriously. I'd much rather make a living as an offroad outfitter and trail guide. But alas, that's not possible in this economy. I'm actually waiting for my own industry to recover, so I can resume my 35-year career as an EE. Was laid off seven months ago, but the end of the downturn is in sight. I used to run customer support for a very small semiconductor test equipment company. We would be the very last thing on the chip manufacturer's production line, to do final test and QA on their chips. Half-million dollar systems weighing 500-1000 pounds or so with 100,000 chips on 100 PC boards inside. And I was the "troubleshooter of last resort" for those puppies. Deeply understanding trailvoy systems just took a couple months reading the shop manual cover to cover and keeping up with what members report here are their top failure modes so I get an idea of the statistics.

Some people volunteer at their local animal shelter or art museum when they're between jobs. I volunteer here on trailvoy. :tiphat
 

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2004 chevy trailblazer_ls
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Discussion Starter · #15 ·
sweet job makin bucks were glad to have you here on trailvoy and im glad to be a member. i dont know alot about cars but i know enuff thats when you and all the other trailvoy members come in handy to save big bucks at the dealership a.k.a stealership :thx
 
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